src/lib/timer.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright 2014 Google Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc.
  18  */
  19
  20 #include <console/console.h>
  21 #include <timer.h>
  22 #include <delay.h>
  23 #include <thread.h>
  24
  25 __attribute__((weak)) void init_timer() { /* do nothing */ }
  26
  27 void udelay(unsigned usec)
  28 {
  29         struct stopwatch sw;
  30
  31         /*
  32          * As the timer granularity is in microseconds pad the
  33          * requested delay by one to get at least >= requested usec delay.
  34          */
  35         usec += 1;
  36
  37         if (!thread_yield_microseconds(usec))
  38                 return;
  39
  40         stopwatch_init_usecs_expire(&sw, usec);
  41
  42         while (!stopwatch_expired(&sw))
  43                 ;
  44 }